BIM technology involves collaboration across multiple disciplines and enterprise units. Therefore, the sharing and exchange of data among these various parties are essential for the successful development of BIM. True data sharing and coordination in building information require that all participants adhere to the same industry standards. The following are some of the most commonly used international BIM standard formats:
(1) Gbxml Format
Gbxml stands for Green Building XML (Green + Extensible Markup Language). It is the most widely recognized and frequently used format in the industry. GbXML facilitates interoperability across multiple software platforms, reducing the need to manually recreate models in different programs. This format is often considered a data subset specifically tailored for green building projects.
(2) IFC Format
IFC (Industry Foundation Classes) defines the detailed information related to buildings and construction projects, providing a standardized way to represent real-world objects. The data description language used by IFC is user-oriented and standardized, enabling detailed data representation and comprehensive information definition.
First released in January 1997, IFC has evolved through six versions. IFC2x3 is currently the most widely supported by BIM software on the market. The latest version, IFC2x4, released at the end of 2010, better supports the collaborative design processes prevalent in today’s industry.
The IFC standard models data relationships using concepts such as inheritance, polymorphism, encapsulation, abstraction, and referencing. It thoroughly describes engineering phenomena and the interconnections between different pieces of information through uniquely described objects and their relationships.
(3) DWG Format
DWG (AutoCAD Drawing) is a proprietary file format used by AutoCAD and other related software to store design data. It serves as a universal format for both 2D and 3D graphics within AutoCAD. Originating from the InteractCAD software in the 1970s, DWG remains widely used because many design firms still rely on traditional drafting methods with AutoCAD as their main tool.
To support data exchange, Revit, a key BIM software, can export drawings in DWG format, enabling easier collaboration and data sharing between parties.
(4) Other Formats
DXF (Drawing Interchange Format) is an open vector data format designed for interoperability between AutoCAD and other software. Although DXF and DWG primarily describe 3D geometric data, they lack support for abstract data such as performance, processes, or costs. As a result, DXF alone cannot represent a complete BIM dataset. It is typically used as an intermediate format for tasks requiring only 3D geometry, such as visualizing building appearances or rendering models.
IDF (Instrument Definition File) is a two-dimensional text-based format that uses defined data structures. It is commonly used by energy simulation software like EnergyPlus. IDF serves as a medium for managing and transmitting BIM data related to energy analysis.
For example, 3D IFC data can be converted into the IDF format and imported into EnergyPlus for energy consumption simulations. The simulation results can then be fed back into GBXML data through the Green Building Studio (GBS) cloud platform for further performance analysis.
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